www.megadrum.info

I'm having some frustrating issues wiring my LCD.

* Cannibalizing IDE cables seems like a great idea. However, separating out chunks from a 80 wire ribbon cable is difficult. It's too easy to pull the insulation off the spider hair wires while pulling them apart. Does anyone have a tip for effortless and repeatedly successful separation of the IDE strands? It gets to be more problematic when you have to separate individual strands to connect to the actual LCD... that's 16 wires you have to separate without screwing it up.
* The 16P connectorassembly I have simply doesn't crimp and maintain the individual wire integrity. I've tried a handful of times and it keeps bridging adjacent wires which makes it useless. I can't figure out why, but I'm assuming user error. Comparing the IDE connector I pulled the ribbon cable from the 16P has significantly larger crimps inside so I'm guessing that's the reason I'm having such difficulty. I've gotten around that issue by separating out 16 individual wires and manually inserting them into the crimp pins. But now I have to successfully separate out 16 individual wires on BOTH ends. By the time I keep cutting back the ribbon due to me pulling the entire wire core out of the insulation my cable is getting shorter and shorter.

Overal I've easily spend 2 hours trying to make one silly ribbon cable. It's about like me trying to print the board GIFs, a lesson in absolute head banging frustration. I could have just soldered straight bell wire to header pins then to the LCD in 10 minutes instead. Which is what I'll probably do at this point. The end result is the same though I lose the ability to quickly disconnect the LCD from the board and it won't look as tidy and attractive.

Lastly, here's the pinouts for my LCD.



Here's a LCD pinout thread which I assume still applies to the V2.5 board: viewtopic.php?f=3&t=131 But I still don't have any idea what pin on the board maps to which pin on the LCD. I thought I could just pull the schematics for the V2.7 board from here viewtopic.php?f=3&t=187 and try to concoct my own mapping but my LCD has pin labels that don't match the schematics such as RS, RW, etc.

You should be using an old type IDE ribbon cable with 40 wires. This type of cables has solid core wires and with it there is no problem with pulling insulation off.
The pinout of your LCD looks all right, just connect pin 1 of the LCD to pin 1 of the connector, 2 to 2 and so on.

That would certainly explain my difficulties. I can't say I've ever dissected a IDE cable so I only have the two I had laying around to compare with. They both have standard 40 contact connectors but 80 wire ribbons using 30AWG sized single core wire. Why? I couldn't tell you. But it'd seem 40 wire ribbons would provide thicker wire and more insulation. I'll have to see if I can find some. Unfortunately I just placed my final order from Mouser or I would've added some to the order.

Look at the LCD I got in my build, it has a 8x2 connector that made my life very very very simple

viewtopic.php?f=3&t=329&p=4467#p4467

Japi, the LCD with the 16P header on it is indeed fantastic! I think in general most users want a MegaDrum because it's theoretically cheap compared to other modules. But there's always something to be said for making things faster and easier, too. Having a 16P header on the board and LCD means you just plug in a cable and you're done. Good stuff!

I can confirm that using a 80-wire ribbon instead of a 40-wire ribbon was my issue. I had no problems splitting and stripping the 40-wire IDE cable and it worked perfectly on the first shot with my 16P connector. No bridging of the channels, no issues separating them, worked great. I only wish I'd asked 15 minutes into my 80-wire experience and saved myself a lot of frustration.

Yes, the 80 cable is so thin to manipulate! Very dificult.
It's working now? Photos!?!!

You can check my build thread for updates. I won't have the remainder of my components for a couple of days. Namely the LCD header and programming cable ends.

And for the cable to the jacks, I pulled the wires apart, put a piece of crimping hose on each pair and colored the even numbers of the wires black with a marker. This way making mistakes is reduced to the minimum.
GyRo.